Propulsion system



March 21, 1961 J, co

PROPULSION SYSTEM Filed Dec. 25, 1957 PROPULSION SYSTEM Marshall J. Corbett, Willoughby, Ohio, assignor to 'ghompsou Rama Wooldridge Inc, a corporation of bio Filed Dec. 23, 1957, Ser. No. 704,467

13 Claims. or. 114-429 This invention relates to a propulsion system energized by mono-propellant and Water. The systems of this invention are particularly useful in propelling underwater vehicles.

More specifically, this invention deals with a torpedo which utilizes a. gelatin or paste-like fuel and water for operation. The fuel supplies energy for propulsion, and

the water is used as a diluent to cool the gaseous products of combustion of the fuel and to feed the fuel to the combustion chamber.

A feature of this invention resides in the utilization of the water medium in which a water vehicle operates to control a mono-propellant fuel for energizing the propulsion device of the vehicle. Heretofore, propulicn systems for water vehicles had to be quite bulky for carrying sufiicient fuel to drive the vehicle throughout its intended range of operation. Underwater vehicles, of course, had to be furnished with a source of air for combustion or with heavy, bulky electric storage batteries to furnish the driving force. In the present invention, on the other hand, a small compact propulsion system is provided which does not require either oxygen supplying or water supplying compartments, because the energy producing material is a mono-propellant and water for controlling the combustion of this material is taken onboard from the very water medium in which the vehicle operates.

While the invention will hereinafter be specifically described as embodied in an underwater torpedo, it should be understood that the principles of this invention are generally applicable to propulsion devices which do not require oxygen supplying equipment for combustion but which receive some of the medium in which they operate to control the combustion.

While mono-propellant driven vehicles are known, it has not heretofore been feasible to mechanically drive propelling apparatus from the gases of combustion of such fuels due to their excessive temperatures. This invention now makes possible the controlled driving of mechanical apparatus with the decomposition products of mono-propellant.

It is then an object of this invention to provide a propulsion system energized by a propellant having a high temperature decomposition range wherein the decomposition products are reduced in temperature by a diluent received from the body in which the system operates so that the energy in the gases of decomposition are usable to drive mechanical devices.

Another object of this invention is to provide a propulsion system for Water vehicles which utilizes water to control the burning of a mono-propellant fuel for energizing the vehicle.

A further obiect of this invention is to provide an underwater vehicle which is self-propelled and operates without carrying its own internal oxygen or water sup- P y- Another object of this invention is to provide a small 2,975,746 Patented Mar. 21, 1963 ice compact drive for underwater torpedoes which utilize sea Water to control the operation thereof.

Another object of this invention is to provide a monopropellant fuel driven torpedo which uses sea water as a diluent to reduce the volume of gas which must be generated by fuel carried within the torpedo.

A still further object of the invention is to provide a torpedo with a sea water pump which will energize the feeding of a mono-propellant into a combustion chamber and will dilute and cool the products of combustion to temperatures which will not burn up a motor for driving the torpedo.

A still further object of this invention is to provide a torpedo driven with a nutating-type motor energized by a mono-propellant fuel.

A still further object of this invention is to provide a torpedo driven by a nutating disc motor which is initially energized from an igniter to start the torpedo on an underwater course and is then energized by the burning of a mono-propellant extruded from a chamber by pumping water along the course against a piston in the chamber for placing an extrusion force on the mono-propellant. According to this invention, the torpedo includes a decomposition chamber into which a gelatin-like or paste-like mono-propellant fuel is forced from an adjacent chamber. When the mono-propellant fuel is ignited, it undergoes autocombustion to produce flame temperatures between 4,000" to 5,000 P. which are too hot to be utilized in driving any mechanical motor device. Therefore, water is introduced downstream of the flame front to augment the kinetic energy of the burning gases, thereby providing mechanical energy to furnish thrust for propelling the torpedo. The developed energy is also used to drive a pump which transfers a portion of the water from the medium in which the torpedo operates to the decomposition chamber and to energize the piston in the fuel tank for controlling the feeding of the fuel to the decomposition chamber.

Other features, objects and advantages of this invention will be apparent to those skilled in the art from the following detailed description of the annexed sheet of drawings showing a preferred embodiment of the invention.

On the drawings:

'Figure 1 is a perspective view of a torpedo of this invcntion with wall portions cut away to show portions of the propelling system of this invention; and

Figure 2 is a longitudinal cross-sectional view, with parts in elevation, of the nutating disc motor and gear drive assembly for the counter-rotating propellers of the torpedo.

As shown on the drawings:

In Figure 1 there is illustrated the tail end portion of the torpedo which houses the propelling system of this invention and includes a cylindrical casing or wall 11 which tapers down at its tail end to a cone-shape couverging to the propellers at the rear end of the torpedo. Within the shell '11 there is provided a fuel tank 12 with an expulsion piston 13 slidable along the length thereof. A closure disc 14 spans the cylindrical casing 11 just ahead of the illustrated position of the piston 13 to provide a fiuidqtight chamber 15 between the disc and piston. This chamber receives sea water from an inlet 16 fed by a conduit 17 under the control of a valve 21 which regulates the overboard spillage from opening 22 and is coupled by a tube 23 to a coupling 24 that is supplied by water under pressure from a tube 25 fed from a sleeve-type pump 26. The pump 26 receives sea water through an inlet tube 27 vented to an inlet opening 28 in the casing 11. The pump 26 discharges the sea water through tube 25 connected through the coupling 24 with 3 a tube 3h leading to a cylindrical container 31 on the rear end of the tank 12 and surrounding a casing 32 to provide a cooling jacket therefor. The container 31 provides a chamber '33 surrounding the casing 32, and the casing 32 provides a combustion chamber .34 receiving fuel from the fuel tank 1.2. Sea water from the chamber 33 bleeds through holes 35 into the outlet passage 38 for the combustion chamber 34 so as to admix water with the burning gases of combustion leaving the combustion chamber 34. An igniter 37 initiates combustion in the chamber 34 either by a spark-gap, or by setting off a combustible charge in a cartridge provided in the igniter. The leading ends of the rods of gelatin or paste like fuel extruded through the multi-hole nozzle 36 will thus be ignited.

A conduit 38 receives-the burning gases of decomposition from the mono-propellant fuel ignited in the combustion chamber 34 and in a somewhat cooled or diluted condition because of the sea water introduced through the holes 35.

A mutating disc motor 41 has a housing 42supporting a disc 43 for nutating movement. The gases from the conduit 38 are introduced into the housing 42 on one side of the separator plate 43a which divides the housing into inlet and outlet chambers. As is conventional in mutating disc motors, the disc 43 has a slot receiving the plate 43a therethrough and as the disc nutates on its bearings, the slotted portion of the disc slides over the separator plate 43a.

The-disc 43 has a center ball portion 43briding on spherical bearing portions 42a of the housing. A shaft 44- is mounted in the center ball 43b of the disc and projects rearwardly therefrom to terminate in an enlarged hollow head 44a containing a roller hearing assembly 45. The roller bearing assembly is mounted on the pin journal 46a of a hollow crankshaft 46 which is counterweighted at 47.

i The crankshaft 46 is rotatably mounted on roller bearing 51 carried by a flanged partition wall 48 of a cylindrical housing 49 mounted on the rear end of the motor casing 42, and also on a second smaller set of roller bearings 51 mounted in a recess provided in an end head 50 of the casing 459.

A gear 52 is splined. onto a tube 53 which in turn is splined inside of the rear end of the hollow crankshaft 46. This gear 52 meshes with a planet gear 54- which is engaged with a gear 55 extending through the gear 54 and having a shaft internally splined therein and driving a gear 56 meshed with a gear 57 on the input shaft 61 to the driving cylinder 62 of the sleeve pump 26. Bearings 58 rotatably support the gear 55. This gear 55 extends rearwardly beyond the gear 54 and is meshed with a gear 63 mounted on the inner concentric drive shaft 64 driving the rear-most propeller 65.

The gear 54 also meshes with the inner toothed portion 68 of a cylindrical casing or a ring gear 65 having a ring of teeth 66 at the rear end thereof meshed with a large diameter gear 67 on the outer concentric drive shaft 71 for the forward propeller 72.

As described above, the driving gases are fed to the nutating motor casing 42 on one side of the partition plate 43a. Exhaust gases are vented through a conduit on the opposite side of the partition plate 43 having an outlet 73 opening through the casing 11 of the torpedo.

As better shown in Figure 2 the mutating disc 43 is supported in the housing 42 for nutating movement on the gearing walls 42a which support the spherical core or center of the disc. The output shaft 44 of the nutating disc has a Washer '74 tightly secured to a lip or shoulder 75 of the disc by a bolt/76. The journal pin 46a of crankshaft '46 supports the inner race 81 of the roller bearing assembly 45. This inner race is held against a shoulder on the crankpin by a nut 82 threaded on the end of the crankpin to abut the outer end of the inner race.

The outer race 83 of the roller assembly has an arcuate interior to accommodate rocking movement of the nutating disc shaft 44 While maintaining contact with the ring of roller bearings 45.

Roller bearings 51, as explained above, rotatably mount the crankshaft 46 in the casing 49 and this crankshaft drives the gear 52 to drive the gear 54 surrounding a gear 55 which also drives the sleeve pump through the shaft and gear trains 56 and 57. The toothed casing or ring gear is meshed with the gear 54 and also with the gears? to drive the propeller shaft 71 in onedirection while the gear 63 is meshed with the gear 55 to drive the propeller shaft 64 in the opposite direction.

Ball bearings 84 support the outer drive shaft 71 from the support housing. Bolts such as 35 secure separator blocks 86 and 87 to the rear end 5t! of the housing 49}.

The inner drive shaft 6 is separated from the gear 52 by a spacer such as 91 and is supported in the outer drive shaft by roller bearings 92 and ball bearings $3.

The torpedo propelling system of this invention is tially activated by energization of the igniter 37 such as by supplying electrical energy thereto through wires 94. This igniter may be a cartridge of compressed carbon dioxide or may be a mono-propellant or an explosive mixture. Gas released by the igniter into the decomposition or combustion chamber 34 is under suificient pressure to be forced through the passageway 38 to initiate nutation of the disc 43. The nutation of the disc is converted into rotary motion of the crankshaft 46 and gear 52. Rotation of the gear 52 in one direction effects rotation of gears 54 and55 in the opposite direction. Gear 53 then drives the rotary member 65 causing this member to rotate in the same direction as the gear 52. Gear 67 is locked to the member 65 and rotates in the same direction therewith. This causes drive shaft 71 and forward propeller 72 to rotate in one direction While drive shaft 64 and propeller 65 rotates in the opposite direction. The counter-rotating propellers are reversely pitched to drive the torpedo foiward, and the counterrotation is used to otfset against the effect of a propeller tending to turn the vehicle which it drives. The various gearratios are chosen so that the magnitude of the angular velocity of each propeller is equal.

The rotation of gear 56 drives gear 57 to energize the sleeve pump 25 for pumping sea water to the cou pling Z4 and thence through the tube 17 to the chamber behind the piston '13 and also through the tube 2% to the chamber 33. The control valve 21 is set to determine the amount of sea water to be fed to the chamber 13 for controlling the rate of movement of the piston and the rate of extrusion of the propellant through the nozzle The propellant extruded through the nozzle 36 enters the decomposition chamber 34 in the form of rods and the leading ends of these rods are ignited by the igniter 37. The fuel will yield high energy gas in chamber 34. This gas leaves the chamber through the passage 38 and is cooled and diluted by sea water received through the holes 35. The gases entering the nutating motor housing 52 are thus maintained at a sufiiciently low temperature so that the motor will not be adversely affected. The rate at which fuel enters the decomposition chamber 34 depends upon the pressure on the expulsion piston 13 which, in turn, depends upon the setting of the control valve 21. Thus, the control valve 21 efiectively controls the burning rate of the fuel, and consequently, the pressure developed in the decomposition chamber 34.

The high energy gases diluted with sea water are fed on into the motor chamber on one side of the separating plate 43 and drive the nutating disc to be expelled on the opposite side of the separating plate 43a through the outlet 73.

The gases developed in the decomposition chamber 34 are effective to continue the cycle, and the propellers are thus continually driven until the fuel is exhausted from the fuel tank 12.

The water in the water chamber 33 serves to cool the outer walls of the decomposition chamber 34. Salt in the sea water is molten at the temperatures at which it is introduced into the nutating disc motor, and this molten salt can actually serve as a lubricant for the motor parts.

As indicated, the mono-propellant fuel is an extrudible plastic viscous slurry or a gelatinous material. Numerous suitable mono-propellant mixtures can be made into this form. Such mixtures preferably comprise a stable dispersion of a finely-divided, insoluble solid oxidizer in a continuous matrix of an oxidizable liquid fuel. The liquid fuel can be any oxidizable liquid, preferably an organic liquid containing carbon and hydrogen. Such liquid fuels include hydrocarbons such as triethyl benzene, dodecane and the like; compounds containing oxygen linked to a carbon atom such as esters including methyl rnaleate, diethyl phthalate, butyl oxalate, and the like; alcohols such as benzyl alcohol, triethylene glycol and the like; ethers such as methyl o-naphthyl ether and the like, and many others.

The solid oxidizer can be any suitable, active oxidizing agent which yields an oxidizing element such as oxygen, chlorine or fluorine readily for combustion of the fuel and which is insoluble in the liquid fuel vehicle. Such oxidizers include inorganic oxidizing salts such as amrnonia, sodium and potassium perchlorate or nitrate and metal peroxides such as barium peroxide.

Gelling agents for imparting the desired cohesiveness and flow characteristics to the plastic mixture include natural and synthetic polymers such as polyvinyl chloride, polyvinyl acetate, cellulose esters such as cellulose acetate, cellulose ethers such as ethyl cellulose, metal salts of higher fatty acids such as the sodium or magnesium stearates and palmritates.

The amount of oxidizer is preferably at a stoichiometric level with respect to the liquid fuel, although minimum concentrations of solid oxidizer as low as 40% by weight are operative. In general, the oxidizer will constitute about 65% by weight of the mixture. A preferred operative mono-propellant includes a gel composed of up to 50% by weight of a liquid fuel, from 40 to 65% by weight of an oxidizer and from 3 to by weight of a gelling agent. A specific operative fuel can be composed of about 50% by weight of solid oxidizers such as potassium perchlorate, about 45% by weight of liquid fuel such as methyl benzene, and about 5% by weight of a gelling agent such as ethyl cellulose. It is to be understood, however, that this invention is not limited to use with any particular mono-propellant mixture.

It thus is seen that this invention provides a propelling system especially adapted for a torpedo which requires no internal air or water supply and thereby effects a conservation of space and weight.

It is apparent to those skilled in this art that many numerous modifications and departures from the specific illustrated embodiment of the invention may be made without departing from the scope of the invention. The invention is, therefore, to be construed as limited only by the spirit and scope of the appended claims.

I claim as my invention:

l. A propelling system for a vehicle passing through an ambient medium which comprises a motor for driving the vehicle, a mono-propellant fuel supply in said vehicle, a decomposition chamber receiving mono-propellant from said supply for feeding energizing gases to drive the motor, a pump driven by the motor for controlling the feeding of mono-propellant into the decomposition chamber, means venting said pump to the ambient medium to utilize said medium as loading means for forcing the mono-propellant into the decomposition cham- 6 her, and an igniter for initiating driving of said motor and decomposition of said mono-propellant.

2. A vehicle adapted to be projected through an ambient medium which comprises a motor for driving said vehicle through said medium, a mono-propellant fuel tank on said vehicle, a piston for extruding monopropellant from said tank, a decomposition chamber receiving extruded mono-propellant from said tank, means for feeding products of decomposition from said chamber to said motor for energizing the motor, and a pump driven by said motor receiving ambient medium and for forcing said medium against said piston to control the rate of extrusion of mono-propellant into the decomposition chamber and for diluting the burning gases be fore they reach the motor.

3. A propelling system for a vehicle which travels under water comprising, a supply of mono-propellant fuel on said vehicle adapted to decompose to provide a gas, a chamber for combining said gas from said fuel with water to cool and dilute said gas, means for releasing said diluted cooled gas through energy conversion means which translates the kinetic energy of the gas to mechanical energy, and a pump and a propeller driven by said mechanical energy, the driven propeller providing thrust for propelling said vehicle through the water and the pump transferring a portion of the water under which said vehicle is propelled to said chamber.

4. A propelling system for an underwater torpedo comprising, a fuel tank, a fuel decomposition chamber, a fuel extrusion nozzle between the tank and chamber, a nutating disc motor having an inlet receiving gases from said decomposition chamber and an outlet for discharging spent gases overboard, a crankshaft driven by said nutating disc motor, inner and outer concentric drive shafts, gears driven by said crankshaft and connected to said inner and outer concentric drive shafts whereby rotation of said crankshaft causes said concentric drive shafts to rotate in opposite directions, first and second propellers mounted on said outer and inner concentric drive shafts respectively, and a pump driven by said gears receiving water from the water medium through which said torpedo is driven by the propellers to dilute said gases with water before reaching said motor.

5. A propelling system for a water vehicle comprising, a supply of fuel on said vehicle consisting essentially of a paste-like mixture of a mono-propellant fuel which decomposes to provide hot gases having high kinetic energy, a chamber for combining said gases with water, a gas driven motor, and means for feeding the water diluted gases to said motor to propel said vehicle.

6. A propelling system for a vehicle which travels through water comprising, a supply of mono-propellant fuel on said vehicle, a water actuated feed device for said fuel, a pump for energizing the feed device, a chamber for burning said fuel to provide a high energy gas at a rate controlled by said feed device, means for receiving water from said pump for diluting said gas with water to cool said gas, and a driving motor for said vehicle driven by the cooled diluted gas.

7. A propelling system for a vehicle which travels through water comprising, a supply of gelatinous monopropellant fuel on said vehicle, water energized means for extruding said fuel at a desired rate, a combustion chamber receiving the extruded fuel to produce high energy gases, a gas motor driven by said gases for driving said vehicle, and a pump driven by said motor for pumping water to said water energized means to control the rate of extrusion of said fuel thereby controlling the rate of gas generation and the speed of said vehicle.

8. An underwater torpedo which comprises a main casing, a fuel tank in said casing for containing gelatinous mono-propellant fuel, a plunger means in said fuel tank for loading said fuel to extrude the fuel from the tank at a desired rate, extrusion means coacting with said tank, a combustion chamber receiving extruded fuel from said tank, means for igniting extruded fuel in said combustion chamber to produce high energy gases by decomposition of the mono-propellant, a gas engine driven by said high energy gases, transmission means driven by said engine, propeller means driven by said transmission means to drive the torpedo underwater, a pump driven by said transmission means having an inlet opening in said casing for receiving water, a control valve receiving water from said pump and regulating flow of said water to said plunger means to thereby control the rateof extrusion of said fuel from said fuel tank, and means receiving water from said pump for diluting gases developed in said combustion chamber to cool the gases before they reach the engine.

9. An underwater vehicle which comprises a vehicle housing, a fuel tank for gelatinous mono-propellant fuel in said housing, an extrusion outlet forsaid tank, a decomposition chamber receiving extruded fuel from said extrusion means, means initiating decompositionof said fuel in said chamber, a nutating disc motor driven by gases of decomposition from said chamber, transmission mechanism driven by said motor, propellers for driving said vehicle driven by said transmission means, a pump dniven by said transmission means receiving water from outside said housing, means energized by water from said pump to load the fuel in the fuel tank for controlling the rate of extrusion into said chamber, valve means regulating said loading means to maintain a desired rate of extrusion, and means receiving water from said pump for cooling the gaseous decomposition products before they reach said motor.

10. A propelling system for a torpedo comprising, a fuel tank and decomposition chamber with a perforated disc therebetween, a mutating disc motor whose inlet is coupled to the output of said decomposition chamber by a conduit, a rotatable crankshaft drivingly interconnected to said nutating disc motor, inner and outer concentric drive shafts, reduction gears driven by said crankshaft and connected to said inner and outer concentric drive shafts whereby rotation of said crankshaft causes said concentric drive shafts to rotate in opposite directions, first and second propellers mounted on said outer and inner concentric drive shafts respectively, a water chamber surrounding said decomposition chamber and communicating therewith through small openings, and a sleeve pump driven by said reduction gears and having an input conduit which communicates with an opening in the torpedo outside Wall and an output conduit which communicates with said water chamber and an'expansible chamber bounded onone side by a piston slidable within said fuel tank. 1

11. A propelling system for a torpedo comprising, a fuel tank and decomposition chamber with a perforated disc therebetween, a mutating disc motor whose inlet is coupled to the output of said decomposition chamber by a conduit, a rotatable drive shaft driving'ly interconnected to said mutating disc motor, inner and outer concentric drive shafts, reduction gears driven by said crankshaft and connected to said inner and outer concentric drive shafts whereby rotation of said crankshaft causes the concentric drive shafts to rotate in opposite directions, first-and second propellers mounted on said outer and inner concentric shafts respectively, a water chamber surrounding said decomposition chamber and communi cating therewith through small openings, a sleeve pump driven by said reduction gears and having an input conduit which communicates with an opening in the torpedo outside wall and an output conduit which communicates with said decomposition chamber, a control valve whose input communicates with said output conduit and having two outputs, one communicating with a spillage outlet and the other communicating with an expansible chamber bounded on one side by a piston slidable within said fuel tank, said control valve regulating the pressure within said expansible chamber.

12. A vehicle adapted to be projected through an amhient medium which comprises a. motor for driving said vehicle through said medium, a mono-propellant fuel supply on said vehicle, means for delivering mono-propellant from said supply, a decomposition chamber receiving said mono-propellant from said supply, means for feeding products of decompositionifrom said chamber to said motor for energizing the motor, and means for receiving and impelling ambient medium to control the rate of delivery of mono-propellant into the decomposition chamber and for diluting the products of decomposition before they reach the motor.

13. A propelling system for a vehicle which travels through an ambient medium comprising, a supply of mono-propellant fuel on said vehicle, a feed device for said fuel, means for energizing the feed device, a chamber for burning said fuel to provide a high energy gas at a rate controlled bysaid feed device, means for receiving ambient for diluting said gas with ambient to cool said gas, and a driving motor for said vehicle driven by the cooled diluted gas.

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